JP6905217B2 - A cured film made by curing a thermosetting polyphenylene ether resin composition. - Google Patents

Description

The present invention relates to a cured film obtained by curing a thermosetting polyphenylene ether resin composition.

In the field of electronic materials, there is a demand for resins having low dielectric constant, high strength, and high heat resistance, and also having excellent adhesiveness to other materials such as polymer materials and copper foil. Polyphenylene ether (hereinafter, also referred to as “PPE”) oligomer has a low dielectric constant, but has a low molecular weight and is difficult to mold by itself. Therefore, a method of imparting thermosetting property to a PPE oligomer and using it as a thermosetting resin has been proposed. For example, Patent Document 1 (Japanese Unexamined Patent Publication No. 2004-59644) discloses a PPE oligomer having a vinyl group at the end and a cured product thereof. However, there is no disclosure in the document relating to the combination of PPE oligomers with other thermoplastic resins. Patent Document 2 (Japanese Unexamined Patent Publication No. 2006-83364) discloses a thermosetting resin obtained by heat-treating a PPE oligomer having a vinyl group at the end and a styrene block copolymer. Patent Document 3 (Japanese Unexamined Patent Publication No. 2015-090954) discloses a thermosetting resin obtained by heat-treating a composition containing a PPE oligomer, a thermoplastic elastomer, and a metal oxide. Patent Document 4 (Japanese Unexamined Patent Publication No. 9-87473) describes a resin composition obtained by blending a rubber-modified polystyrene-based resin composition with a small amount of oligophenylene ether. Patent Document 5 (Japanese Unexamined Patent Publication No. 2012-119446) describes a laminate of a resin in which oligophenylene ether and a styrene-butadiene elastomer are mixed and a liquid crystal polymer. Patent Document 6 (Japanese Unexamined Patent Publication No. 2013-151638) describes a coverlay film composed of an adhesive layer containing an oligophenylene ether and a styrene-butadiene elastomer and a film substrate.

Japanese Unexamined Patent Publication No. 2004-59644 Japanese Unexamined Patent Publication No. 2006-83364 JP-A-2015-090954 Japanese Unexamined Patent Publication No. 9-87473 Japanese Unexamined Patent Publication No. 2012-119446 Japanese Unexamined Patent Publication No. 2013-151638

As a result of preliminary examination of the techniques described in Patent Documents 2 to 6, the inventors have found that the resin disclosed in the document does not have sufficient adhesiveness to other materials such as other polymer materials. It was found that the cause of this is that other resins such as block copolymers do not have functional groups. From the above, it is an object of the present invention to provide a thermosetting polyphenylene ether resin composition having a low dielectric constant and excellent adhesiveness.

The inventors have found that the above problems can be solved by combining a PPE oligomer with a specific epoxy group-containing styrene-based thermoplastic resin, and have completed the present invention. That is, the above-mentioned problem is solved by the following invention.
[1] 97 to 30% by mass of (A) a thermosetting polyphenylene ether oligomer having a number average molecular weight of 500 to 8,000, and (B) 1 to 20 (g) of MFR (190 ° C. under a 2.16 kg load). 3 to 70% by mass of epoxy group-containing styrene-based thermoplastic resin (/ 10 minutes)
A cured film obtained by curing a thermosetting resin composition containing.
[2] The cured film according to [1], wherein the component (B) is a block copolymer having a polystyrene block.
[3] The cured film according to [1] or [2], wherein the component (A) has a styrene double bond at the end.
[4] The cured film according to any one of [1] to [3], wherein the component (B) is a polystyrene block and a block copolymer having a polyconjugated diene block or a hydrogenated polyconjugated diene block.
[5] A solution preparation step of dissolving the thermosetting composition in an organic solvent to obtain a solution.
A casting step of casting the solution to form a film precursor, and a curing step of heating the film precursor.
The method for producing a cured film according to any one of [1] to [4], which comprises.
[6] A laminate containing the cured film and super engineering plastic film according to any one of [1] to [4] above.
[7] A laminate containing the cured film and copper foil according to any one of the above [1] to [4].

Hereinafter, the present invention will be described in detail. In the present invention, the notation "XY" includes the values X and Y at both ends.

1. 1. Thermosetting resin composition The thermosetting resin composition is a composition that gives a cured product having a three-dimensional crosslinked structure by heating. The thermosetting resin composition of the present invention contains a component (A): a specific thermosetting polyphenylene ether oligomer, and a component (B): an epoxy group-containing styrene-based thermoplastic resin.

(1) Thermosetting polyphenylene ether oligomer (component A)
The thermosetting polyphenylene ether oligomer is an oligomer of a polyphenylene ether having a thermosetting functional group. Oligomers are low molecular weight polymers. Specifically, in the present invention, the number average molecular weight of the PPE oligomer is 500 to 8,000, preferably 800 to 5000. The number average molecular weight can be measured by GPC.

Polyphenylene ether (PPE) is a polymer having a repeating structure in which phenylene groups are linked by ether bonds. Preferred PPE includes a polymer containing 90 mol% or more, preferably 95 mol% or more, of the unit represented by the following chemical formula (1).

In the formula, R ₁ , R ₂ , R ₃ and R ₄ are independently hydrogen atom, halogen atom, primary or secondary alkyl group having 1 to 7 carbon atoms, phenyl group, haloalkyl group and amino. It is selected from the group consisting of an alkyl group, a hydrocarbon oxy group, and a halohydrocarbon oxy group in which a halogen atom and an oxygen atom are bonded via at least two carbon atoms. The haloalkyl group, aminoalkyl group, and hydrocarbon oxy group preferably have 1 to 7 carbon atoms. The halohydrocarbon oxy group preferably has 2 to 7 carbon atoms.

R ₁ and R ₂ are preferably primary alkyl groups having 1 to 3 carbon atoms independently of each other, and more preferably methyl groups. Further, R ₃ and R ₄ are preferably hydrogen atoms.

Examples of the unit other than the unit represented by the chemical formula (1) include the unit represented by the following (2).

R ₁ ', R ₂ ', R ₁ ", R ₃ ", and R ₄ "are independently halogen atoms or primary or secondary alkyl groups or phenyl groups having 6 or less carbon atoms. ₃ ', R ₄ ', and R ₂ "are independently hydrogen atoms, halogen atoms, primary or secondary alkyl groups having 6 or less carbon atoms, or phenyl groups. The oxygen atom of the unit represented by the formula (2) is bonded to the benzene ring of the unit represented by the formula (1). PPE oligomers containing the unit of formula (2) are described, for example, in Patent Document 1.

Specific examples of PPE include poly (2,6-dimethyl-1,4-phenylene ether), poly (2,6-diethyl-1,4-phenylene ether), and poly (2,6-dipropyl-1,4). -Phenylene ether), poly (2-methyl-6-ethyl-1,4-phenylene ether), poly (2-methyl-6-propyl-1,4-phenylene ether), poly (2-ethyl-6-propyl) -1,4-phenylene ether), 2,6-dimethylphenol / 2,3,6-trimethylphenol copolymer, 2,6-dimethylphenol / 2,3,6-triethylphenol copolymer, 2,6 Includes −diethylphenol / 2,3,6-trimethylphenol copolymer and 2,6-dipropylphenol / 2,3,6-trimethylphenol copolymer. Of these, poly (2,6-dimethyl-1,4-phenylene ether) is preferable as the PPE.

The thermosetting PPE oligomer of the present invention has thermosetting functional groups at both ends. Examples of the thermosetting functional group include an ethylene-based double bond group, an epoxy group, an imide group, an acetyl group and the like, but in the present invention, an ethylene-based double bond group is preferable. Among the ethylene-based double bond groups, a styrene-based double bond group in which an ethylene-based double bond group is bonded to a phenylene group is particularly preferable. The PPE oligomer having a styrene-based double bond group at the terminal is represented by the following chemical formula (3). Since the polystyrene unit generated by the reaction of the styrene-based double bond groups is compatible with the PPE unit, this cured product has excellent mechanical properties.

In the formula, PPE represents a PPE unit. R _{10 to} R ₁₃ are independently hydrogen atoms or linear or branched alkyl groups having 1 to 4 carbon atoms. n is 0-4 indicates the number of _{R 13} groups. In order to increase the reactivity, R _{10 to} R ₁₃ are preferably a methyl group or a hydrogen atom, and more preferably a hydrogen atom. Similarly, n is preferably 0 or 1, more preferably 0.

The thermosetting PPE oligomer can be produced by modifying the end of the PPE oligomer produced by a known method. For example, it can be produced by the method described in JP-A-2009-161725 or JP-A-2011-68713. Specifically, it can be produced by reacting a phenylene ether oligomer having phenol hydroxyl groups at both ends with vinylbenzyl chloride to convert the phenol hydroxyl groups into vinylbenzyl ether.

(2) Epoxy group-containing styrene-based thermoplastic resin (component B)
The epoxy group-containing styrene-based thermoplastic resin is a thermoplastic resin having a polystyrene unit and containing an epoxy group. In the present invention, a styrene block copolymer containing an epoxy group is preferable. The copolymer is a polymer obtained by subjecting a styrene block copolymer to epoxy modification. The styrene block copolymer is a block copolymer of styrene and a conjugated diene compound. Examples of the conjugated diene compound include butadiene, isoprene, 1,3-pentadiene, 3-butyl-1,3-octadiene, and butadiene or isoprene is preferable. The styrene block copolymer may be a polyconjugated diene block that has been hydrogenated, but is preferably not hydrogenated from the viewpoint of obtaining a higher effect. In the present invention, a styrene-butadiene-styrene triblock copolymer is preferable because of its availability. Such a styrene block copolymer or a hydrogenated product thereof can be prepared, for example, by the method described in Japanese Patent Application Laid-Open No. 40-23798 and JP-A-59-133203.

Epoxidizing a styrene block copolymer means epoxidizing a double bond in the main chain of the copolymer or introducing a compound having a glycidyl group into the copolymer. In the present invention, the former is preferable. An example of the structure of the former epoxy group-containing styrene block copolymer is shown below.

The method for epoxidizing the double bond is not particularly limited, but a known method such as treating the styrene block copolymer with a peroxide can be used. Further, the method of introducing the compound having a glycidyl group into the styrene block copolymer is not limited, but it can be introduced by graft-copolymerizing the compound having a glycidyl group into the styrene block copolymer. At this time, the compound having a glycidyl group is preferably introduced into the polyconjugated diene block (for example, butadiene block) of the styrene block copolymer.

Since the polystyrene block in the styrene block copolymer containing an epoxy group is almost completely compatible with the PPE oligomer of the component (A), the decrease in compatibility can be avoided by introducing the epoxy group into the polyconjugated diene block. can.

The epoxy group content in the epoxy group-containing styrene-based thermoplastic resin can be expressed by the oxylan oxygen concentration. The oxylan oxygen concentration can be determined by titrating the mass% of oxylan oxygen derived from the epoxy group in the block copolymer according to ASTM-1652 using an acetic acid solution of hydrogen bromide. The oxygen concentration of oxylan is preferably 0.1 to 8% by mass, more preferably 0.2 to 5% by mass, still more preferably 0.4 to 3% by mass. If the oxygen concentration of oxylan is out of these ranges, the moldability of the composition may be insufficient, which is not preferable.

The content of styrene in the epoxy group-containing styrene-based thermoplastic resin is preferably 20 to 70% by mass, more preferably 35 to 50% by mass.

The MFR of the epoxy group-containing styrene-based thermoplastic resin is 1 to 20 (g / 10 minutes), preferably 2 to 15 (g / 10 minutes), and 3.0 to 9.0 (g / 10 minutes). More preferred. The MFR is measured in accordance with JIS K7210 under the conditions of a resin temperature of 190 ° C. and a measurement load of 21 N (under a 2.16 kg load). If the MFR is less than 1 (g / 10 minutes) or more than 20 (g / 10 minutes), the affinity with the component (A) is lowered, and the appearance of the obtained molded product is deteriorated.

(3) Mixing ratio The mixing ratio of the components (A) and (B) is 97 to 30% by mass: 3 to 70% by mass, preferably 85 to 45% by mass: 15 to 55% by mass. If the mixing ratio of the component (A) is less than the lower limit, the heat resistance is lowered, and if it exceeds the upper limit, the adhesiveness is not sufficient.

(4) Other Ingredients The composition of the present invention preferably contains a solvent. When used as a composition (solution) containing a solvent, it is useful as a raw material for films and coating agents. The solvent is not limited as long as it can dissolve the components (A) and (B), but considering the removal and curability of the solvent during casting, a solvent having a boiling point of 20 to 100 ° C. at normal pressure is preferable. A solvent having a temperature of 35 to 85 ° C. is more preferable. Examples of this solvent include chloroform, dichloromethane and the like. A plurality of solvents may be used in combination. The amount of the solvent is not limited, but the solid content concentration is preferably in the range of 1 to 20% by mass, and more preferably in the range of 2 to 10% by mass.

The composition of the present invention may contain a radical initiator to promote curing. A known radical initiator can be used, and the amount used may be a known amount. Furthermore, the composition of the present invention may contain an inorganic filler, if necessary. Examples of the inorganic filler include silica, talc, mica, calcium carbonate, and wallanite. In addition, a coupling agent, a reinforcing agent, a flame retardant aid, a stabilizer, a pigment, a mold release agent, an impact resistance improving agent such as an elastomer, or the like can be blended. The blending amount thereof is preferably 20 parts by weight or less with respect to 100 parts by mass in total of the components (A) and (B).

(5) Method for Producing Composition The composition of the present invention can be produced as a composition containing the solvent by mixing the components (A), (B), an organic solvent and other components. The mixing temperature is preferably room temperature. It may be heated if necessary, but in this case, it is necessary to prevent the reaction of the components (A) and (B) from proceeding excessively.

2. Cured Film A cured film can be obtained by curing the thermosetting resin composition of the present invention. In the present invention, the film refers to a member having a thickness of 250 μm or less. Specifically, as the cured film, it is preferable to prepare a thermosetting resin composition containing an organic solvent, cast the solution to form a film precursor, and heat the film precursor to cure it. The film precursor can be carried out, for example, by developing the solution prepared in the previous step on a flat plate and drying it. At this time, a known instrument such as a bar coater may be used. The thickness of the film precursor is not limited, but is preferably about 1 to 300 μm.

Next, the film precursor is heated and cured, but the temperature at that time is not limited as long as the reaction proceeds sufficiently. Preferred conditions include a condition in which the total heating time is 20 minutes to 3 hours at 130 to 260 ° C. Curing is preferably carried out by a so-called vacuum press, which heats the film precursor while removing solvents and air bubbles. The degree of pressurization is not limited, but is preferably 1 MPa to 100 MPa, more preferably 3 to 50 MPa. The curing step is preferably carried out in two steps. That is, it is preferable to perform the first stage of heating and pressurizing and then the second stage of heating and pressurizing to completely cure. The phase structure of the cured film of the present invention is such that the component (A) is a continuous phase and the component (B) is a dispersed phase, the component (B) is a continuous phase and the component (A) is a dispersed phase, or the component (A). ) And the component (B) are in a co-continuous phase.

The cured film of the present invention provides a cured product having excellent dielectric properties, adhesiveness, and mechanical properties, and is therefore useful as an electronic material. In particular, it is useful as a film for printed wiring boards and build-up boards. The cured product can be peeled off by a known method to form a film. The cured product can be used as it is as a coating without peeling.

The cured film of the present invention can also be used as a laminate with a super engineering plastic film. As the super engineering plastic, general super engineering plastics such as polyimide, polyether sulfone, and polyether ether ketone can be used, and polyimide is preferable. Further, the cured film of the present invention can also be used as a laminate with a copper foil.

1. 1. Physical property measurement test (1) Peeling strength After cutting a laminated film of a cured film and a polyimide or a laminated body of a cured film and a copper foil into a sample width of 12 mm and a sample length of 100 mm, JIS Z0237 (2009) at a peeling speed of 50 mm / min. ), A 90-degree peeling test was performed.
(2) A cured film having a dielectric constant and a dielectric loss tangent of 3 cm × 5 cm × 0.5 mm is held in a constant temperature and humidity chamber at 20 ° C. and 60% humidity for 90 hours, and then in the same constant temperature and humidity chamber, a split post manufactured by QWED. The dielectric constant and the dielectric loss tangent of the sample were measured at 10 GHz using a resonator, SPDR type.
(3) Dynamic viscoelasticity Using a cured film with a width of 4 mm and a length of 4 cm, using the Leovibron dynamic viscoelastic automatic measuring instrument DDV-01FP-W manufactured by A & D, the temperature rise rate is 2 ° C./min. Dynamic viscoelasticity was measured at a frequency of 1 Hz, and the storage elastic modulus and the glass transition point were determined.

2. Ingredients Ingredients (A)
A-1: Bifunctional oligophenylene ether (OPE-2St) manufactured by Mitsubishi Gas Chemical Company, Ltd., Mn = 2200

Ingredient (B)
B-1: Epoxy group-containing styrene-butadiene-styrene block copolymer manufactured by Daicel Corporation (Epofriend AT501)
St / Bd = 40/60 wt ratio MFR (190 ° C) = 9 (g / 10 minutes)
Mn = 77600, Mw = 93100
Epoxy equivalent 1100g / eq
Oxylan oxygen concentration (HBr titration) 1.5% by mass
Hydrogenation rate 0% by mass

Ingredient (C)
C-1: Styrene-butadiene-styrene block copolymer (Toughprene 315P) manufactured by Asahi Chemicals Co., Ltd.
Epoxy group-free St / Bd = 20/80 wt ratio MFR (190 ° C) = 15 (g / 10 minutes)

[Example 1]
1.3 g of A-1 and 1.3 g of B-1 were dissolved in 50 mL of chloroform with stirring in a beaker at room temperature for 1 h. The solution was developed on a Teflon (registered trademark) petri dish and dried in a clean oven under a nitrogen atmosphere at room temperature for 8 hours to prepare a cast film. The obtained cast film was treated (first curing) at 200 ° C. and 10 MPa for 20 minutes under reduced pressure using a pressure press (manufactured by Imoto Seisakusho, device name: vacuum heating press device, IMC-11FD type). After that, it was further treated (second curing) at 240 ° C. and 10 MPa for 20 minutes under reduced pressure. In this way, a cured film having a thickness of 0.5 mm and having a good appearance was obtained.

The obtained cured film had a dielectric constant of 2.53 and a dielectric loss tangent of 0.0055. The storage elastic modulus of the obtained cured film at 100 ° C. was 1.0E + 8.7Pa, and the glass transition point was 189 ° C.

Further, the cast film prepared in the same manner as described above is laminated with a polyimide film manufactured by Toray DuPont Co., Ltd. (Kapton R500H, 0.125 mm thickness), heated and pressurized in the same manner as described above using a pressure press, and laminated. The body was prepared. The adhesive strength of the cured film to polyimide was evaluated using the laminate. As a result, the peel strength between the cured film and the polyimide was 1.09 N / mm.
The copper foil of the cured film was heated and pressurized in the same manner as above, except that T9FZ-HTE (18 μm thickness), a rough copper foil manufactured by Fukuda Metal Foil Powder Industry Co., Ltd., was used instead of the polyimide film. The peel strength was evaluated. As a result, the peel strength between the cured film and the copper foil was 1.11 N / mm.

[Comparative Example 1]
A cured film was produced in the same manner as in Example 1 except that C-1 was used instead of B-1. The obtained cured film had a dielectric constant of 2.53 and a dielectric loss tangent of 0.0035. The storage elastic modulus at 100 ° C. was 1.0E + 8.5Pa, and the glass transition point was 188 ° C. Next, in the same manner as in Example 1, a laminate of the cured film and polyimide and a laminate of the cured film and copper foil were prepared and evaluated. The peel strength between the cured film and the polyimide was 0.59 N / mm, and the peel strength between the cured film and the copper foil was 1.15 N / mm.

[Comparative Example 2]
An attempt was made to prepare a cast film in the same manner as in Example 1 using only A-1 without using B-1, but a homogeneous cast film could not be obtained and the physical properties could not be measured.

The cured film of the present invention has a very low dielectric constant and dielectric loss tangent, while the dynamic viscoelasticity shows good results. Furthermore, the cured film showed excellent adhesiveness to other materials.

Claims (6)

(A) 85 to 45% by mass of a thermosetting polyphenylene ether oligomer having a styrene double bond at the terminal and having a number average molecular weight of 500 to 8,000 and (B) MFR (190 ° C. under a load of 2.16 kg). ) Contains 15 to 55% by mass of an epoxy group-containing styrene-based thermoplastic resin having a value of 1 to 20 (g / 10 minutes) .
The total amount of the components (A) and (B) is 100% by mass.
Curing obtained by curing a thermosetting resin composition having an oxygen concentration of oxylane derived from the epoxy group of the component (B) of 1.5 to 8% by mass and a styrene content of 35 to 70% by mass. the film. The cured film according to claim 1, wherein the component (B) is a block copolymer having a polystyrene block. The cured film according to claim 1 or 2, wherein the component (B) is a block copolymer having a polystyrene block and a polyconjugated diene block or a hydrogenated polyconjugated diene block. A solution preparation step of dissolving the thermosetting composition in an organic solvent to obtain a solution.
A casting step of casting the solution to form a film precursor, and a curing step of heating the film precursor.
The method for producing a cured film according to any one of claims 1 to 3, which comprises. A laminate containing the cured film and super engineering plastic film according to any one of claims 1 to 3. A laminate containing the cured film and copper foil according to any one of claims 1 to 3.